as usual simple not easy etc...

level1

figure out deficit/maintenance/surplus calories figure out what behavior changes to maintain consumption levels

level2 (extra work, but really what it's at)

figure out what how you want to look good naked... i.e. body composition figure out workout (usually lifting with some cardio) eat enough protein, eat other macros that can help you do your workouts. ironically dietting is the SIMPLEST... eat enough protein, fill the rest with what makes you feel "best" or helps "best" with your goal (exercise). This doesn't mean it will feel good depending on cut/bulk... just what feels least bad.

Extra work from level2 can make level1 easier - more lean mass from work out-> more maintenance + tdee calories. The process might be easier if you're 25 BMI with 15% bodyfat than 22 BMI with 20% bodyfat. You'll look better too, which let's be real, is what people usually want. Then health.

That's basically it.

But MOST IMPORTANT to recognize that some goals are simply things you're too mentally/physiologically "weak" / incapable of doing. You may simply not be built for to learn behavior changes (i.e. appetite control) for low BMI/BF. Your genes may simply prevent you from building good FFMI to pull off certain build. This stuff is simple, but not easy.